When we are doing GEQO join planning, the current memory context is a
short-lived context that will be reset at the end of geqo_eval(). However,
the RelOptInfos for base relations are set up before that and then re-used
across many GEQO cycles. Hence, any code that modifies a baserel during
join planning has to be careful not to put pointers to the short-lived
context into the baserel struct. mark_dummy_rel got this wrong, leading to
easy-to-reproduce-once-you-know-how crashes in 8.4, as reported off-list by
Leo Carson of SDSC. Some improvements made in 9.0 make it difficult to
demonstrate the crash in 9.0 or HEAD; but there's no doubt that there's
still a risk factor here, so patch all branches that have the function.
(Note: 8.3 has a similar function, but it's only applied to joinrels and
thus is not a hazard.)

On HP/UX, the structs used by ioctl(SIOCGLIFCONF) are named differently than on other platforms, and only IPv6 addresses are returned. Because of those two issues, fall back to ioctl(SIOCGIFCONF) on HP/UX, so that it at least compiles and finds IPv4 addresses. This function is currently only used for interpreting samehost/samenet in pg_hba.conf, which isn’t that critical.

Revert the patch to check if we’ve reached end-of-backup also when doing crash recovery, and throw an error if not. hubert depesz lubaczewski pointed out that that situation also happens in the crash recovery following a system crash that happens during an online backup.

Fix pg_upgrade crash in 9.0 caused by a new cluster database that
doesn't exist in the old cluster; instead throw an error. This was
reported to me by EnterpriseDB testing staff. This bug does not exist
in git head.

On IA64 architecture, we check the depth of the register stack in addition to the regular stack. The code to do that is platform and compiler specific, add support for the HP-UX native compiler.

In particular, if we don't have real ndistinct estimates for both sides,
fall back to assuming that half of the left-hand rows have join partners.
This is what was done in 8.2 and 8.3 (cf nulltestsel() in those versions).
It's pretty stupid but it won't lead us to think that an antijoin produces
no rows out, as seen in recent example from Uwe Schroeder.

Remove the hard-wired assumption that __mips__ (and only __mips__) lacks
dlopen in FreeBSD and OpenBSD. This assumption is outdated at least for
OpenBSD, as per report from an anonymous 9.1 tester. We can perfectly well
use HAVE_DLOPEN instead to decide which code to use.
Some other cosmetic adjustments to make freebsd.c, netbsd.c, and openbsd.c
exactly alike.

Fix SortTocFromFile() to cope with lines that are too long for its buffer.

The original coding supposed that a dump TOC file could never contain lines
longer than 1K. The folly of that was exposed by a recent report from
Per-Olov Esgard. We only really need to see the first dozen or two bytes
of each line, since we're just trying to read off the numeric ID at the
start of the line; so there's no need for a particularly huge buffer.
What there is a need for is logic to not process continuation bufferloads.
Back-patch to all supported branches, since it's always been like this.

This would lead to leaking the PGconn structure after an error detected by
conninfo_array_parse(), as well as failing to return a useful error message
in such cases. Backpatch to 9.0 where the error was introduced.
Joseph Adams

It's possible to restore an online backup without recovery.conf, by simply
copying all the necessary WAL files to pg_xlog. "pg_basebackup -x" does that
too. That's the use case where this cross-check is useful.
Backpatch to 9.0. We used to do this in earlier versins, but in 9.0 the code
was inadvertently changed so that the check is only performed after archive
recovery.
Fujii Masao.

Eventually we might be able to allow that, but it's not clear how many
places need to be fixed to prevent infinite recursion when there's a direct
or indirect inclusion of a rowtype in itself. One such place is
CheckAttributeType(), which will recurse to stack overflow in cases such as
those exhibited in bug #5950 from Alex Perepelica. If we were sure it was
the only such place, we could easily modify the code added by this patch to
stop the recursion without a complaint ... but it probably isn't the only
such place. Hence, throw error until such time as someone is excited
enough about this type of usage to put work into making it safe.
Back-patch as far as 8.3. 8.2 doesn't have the recursive call in
CheckAttributeType in the first place, so I see no need to add code there
in the absence of clear evidence of a problem elsewhere.

On closer inspection, that two-element initcond value seems to have been
a little white lie to avoid explaining the full behavior of float8_accum.
But if people are going to expect the examples to be exactly correct,
I suppose we'd better explain. Per comment from Thom Brown.

The description of the initcond value for the built-in avg(float8)
aggregate has been wrong since it was written. Noted by Disc Magnet.

Prevent intermittent hang in recovery from bgwriter interaction. Startup process waited for cleanup lock but when hot_standby = off the pid was not registered, so that the bgwriter would not wake the waiting process as intended.

Opening a catcache's index could require reading from that cache's own
catalog, which of course would acquire AccessShareLock on the catalog.
So the original coding here risks locking index before heap, which could
deadlock against another backend trying to get exclusive locks in the
normal order. Because InitCatCachePhase2 is only called when a backend
has to start up without a relcache init file, the deadlock was seldom seen
in the field. (And by the same token, there's no need to worry about any
performance disadvantage; so not much point in trying to distinguish
exactly which catalogs have the risk.)
Bug report, diagnosis, and patch by Nikhil Sontakke. Additional commentary
by me. Back-patch to all supported branches.

Add dummy returns before every potential division-by-zero in int8.c,
because apparently further "improvements" in gcc's optimizer have
enabled it to break functions that weren't broken before.
Aurelien Jarno, via Martin Pitt

In ecpg preprocessor, don’t try to look up constants in the test for variable hiding. A constant is not a variable. It worked in most cases by accident, because we add constants to the global list of variables (why?), but float constants like 1.23 were interpreted as struct field references, and not found.

Don’t throw a warning if vacuum sees PD_ALL_VISIBLE flag set on a page that contains newly-inserted tuples that according to our OldestXmin are not yet visible to everyone. The value returned by GetOldestXmin() is conservative, and it can move backwards on repeated calls, so if we see that contradiction between the PD_ALL_VISIBLE flag and status of tuples on the page, we have to assume it’s because an earlier vacuum calculated a higher OldestXmin value, and all the tuples really are visible to everyone.

We have received several reports of this bug, with the "PD_ALL_VISIBLE flag
was incorrectly set in relation ..." warning appearing in logs. We were
finally able to hunt it down with David Gould's help to run extra diagnostics
in an environment where this happened frequently.
Also reword the warning, per Robert Haas' suggestion, to not imply that the
PD_ALL_VISIBLE flag is necessarily at fault, as it might also be a symptom
of corruption on a tuple header.
Backpatch to 8.4, where the PD_ALL_VISIBLE flag was introduced.

In initialize_SSL, don’t fail unnecessarily when home dir is unavailable.

Instead, just act as though the certificate file(s) are not present.
There is only one case where this need be a hard failure condition: when
sslmode is verify-ca or verify-full, not having a root cert file is an
error. Change the logic so that we complain only in that case, and
otherwise fall through cleanly. This is how it used to behave pre-9.0,
but my patch 4ed4b6c54e5fab24ab2624d80e26f7546edc88ad of 2010-05-26 broke
the case. Per report from Christian Kastner.

Time spent executing AFTER triggers is not included in the runtime of the
associated ModifyTable node; in my patch of yesterday I confused queuing of
these triggers with their actual execution. Spotted by Marko Tiikkaja.

Update discussion of EXPLAIN to reflect existence of ModifyTable nodes.

ExecUpdate checked for whether ExecBRUpdateTriggers had returned a new
tuple value by seeing if the returned tuple was pointer-equal to the old
one. But the "old one" was in estate->es_junkFilter's result slot, which
would be scribbled on if we had done an EvalPlanQual update in response to
a concurrent update of the target tuple; therefore we were comparing a
dangling pointer to a live one. Given the right set of circumstances we
could get a false match, resulting in not forcing the tuple to be stored in
the slot we thought it was stored in. In the case reported by Maxim Boguk
in bug #5798, this led to "cannot extract system attribute from virtual
tuple" failures when trying to do "RETURNING ctid". I believe there is a
very-low-probability chance of more serious errors, such as generating
incorrect index entries based on the original rather than the
trigger-modified version of the row.
In HEAD, change all of ExecBRInsertTriggers, ExecIRInsertTriggers,
ExecBRUpdateTriggers, and ExecIRUpdateTriggers so that they continue to
have similar APIs. In the back branches I just changed
ExecBRUpdateTriggers, since there is no bug in the ExecBRInsertTriggers
case.

The previous coding would try to process all SECTION_NONE items in the
initial sequential-restore pass, which failed if they were dependencies of
not-yet-restored items. Fix by postponing such items into the parallel
processing pass once we have skipped any non-PRE_DATA item.
Back-patch into 9.0; the original parallel-restore coding in 8.4 did not
have this bug, so no need to change it.
Report and diagnosis by Arnd Hannemann.

ts_typanalyze.c computes MCE statistics as fractions of the non-null rows,
which seems fairly reasonable, and anyway changing it in released versions
wouldn't be a good idea. But then ts_selfuncs.c has to account for that.
Failure to do so results in overestimates in columns with a significant
fraction of null documents. Back-patch to 8.4 where this stuff was
introduced.
Jesper Krogh

That function was supposing that indexoid == 0 for a hypothetical index,
but that is not likely to be true in any non-toy implementation of an index
adviser, since assigning a fake OID is the only way to know at EXPLAIN time
which hypothetical index got selected. Fix by adding a flag to
IndexOptInfo to mark hypothetical indexes. Back-patch to 9.0 where
get_actual_variable_range() was added.
Gurjeet Singh

Recent releases had a check on rel->rd_refcnt in heap_drop_with_catalog,
but failed to cover the possibility of pending trigger events at DROP time.
(Before 8.4 we didn't even check the refcnt.) When the trigger events were
eventually fired, you'd get "could not open relation with OID nnn" errors,
as in recent report from strk. Better to throw a suitable error when the
DROP is attempted.
Also add a similar check in DROP INDEX.
Back-patch to all supported branches.

Clarify documentation for libpq’s PQescapeBytea to mention the new hex format.

Modify PQescapeStringConn() docs to be consisent with other escaping
functions.
Add mention problems with pre-9.0 versions of libpq using not understanding
bytea hex format to the 9.0 release notes.
Backpatch to 9.0 docs.

Fix improper matching of resjunk column names for FOR UPDATE in subselect.

Flattening of subquery range tables during setrefs.c could lead to the
rangetable indexes in PlanRowMark nodes not matching up with the column
names previously assigned to the corresponding resjunk ctid (resp. tableoid
or wholerow) columns. Typical symptom would be either a "cannot extract
system attribute from virtual tuple" error or an Assert failure. This
wasn't a problem before 9.0 because we didn't support FOR UPDATE below the
top query level, and so the final flattening could never renumber an RTE
that was relevant to FOR UPDATE. Fix by using a plan-tree-wide unique
number for each PlanRowMark to label the associated resjunk columns, so
that the number need not change during flattening.
Per report from David Johnston (though I'm darned if I can see how this got
past initial testing of the relevant code). Back-patch to 9.0.

New versions of libintl redefine setlocale() to a macro
which causes problems when the backend and libintl are
linked against different versions of the runtime, which
is often the case in msvc builds.
Hiroshi Inoue, slightly updated comment by me

Create new errcode for recovery conflict caused by db drop on master. Previously reported as ERRCODE_ADMIN_SHUTDOWN, this case is now reported as ERRCODE_DATABASE_DROPPED. No message text change. Unlikely to happen on most servers, so low impact change to allow session poolers to correctly handle this situation.

Fix error code for canceling statement due to conflict with recovery. All retryable conflict errors now have an error code that indicates that a retry is possible, correcting my incomplete fix of 2010/05/12

reduce_outer_joins() mistakenly treated a semijoin like a left join for
purposes of deciding whether not-null constraints created by the join's
quals could be passed down into the join's left-hand side (possibly
resulting in outer-join simplification there). Actually, semijoin works
like inner join for this purpose, ie, we do not need to see any rows that
can't possibly satisfy the quals. Hence, two-line fix to treat semi and
inner joins alike. Per observation by Andres Freund about a performance
gripe from Yazan Suleiman.
Back-patch to 8.4, since this oversight has been there since the current
handling of semijoins was implemented.